Monday, February 20, 2012

Loginator and SDHC progress

  1. All purely computing parts of the Loginator have now been tested. The power supply, USB, SD card slot, RGB light, and BOOT button all work. The charger circuit itself works, but I installed the LED backwards.
  2. None of the analog parts have been tested. The current sensor was originally too hot to touch when the board was on. I tried to remove it, but in the process of hitting it with the soldering iron I must have fixed it, either that or it is burned out completely. Won't know until I test the analog part. I also realized that I should have gotten the 100V/V part instead of the 20V/V part. This is fixable without any board modification.
  3. I may have made a foolish decision in relation to the RGB light: you can't run the lights as lights at the same time as you use the UART ports. Honestly it's not my fault. There are six PWM pins, but four of them are shared with TX and RX on the two UART ports, one is shared with the chip select pin for the card reader, and one is AD6. Right now I just use the blue and green lights, which overlap UART0. The red one overlaps TX on UART1.
  4. I put into the Logomatic main firmware code some compiler switches so that it can be switched to be Loginator with one switch. This controls where the code looks for the lights and STOP button. With this switch set, the Sparkfun firmware now runs on the Loginator. It is even bug compatible - the first log file is LOF01.TXT. Next is to get Logomatic Kwan adapted the same way.
  5. The SPI port with the SD card on it works, but I haven't tested the other SPI port or either of the I2C ports. I made a silly mistake and wired a pullup resistor to SCK1 (SPI) instead of SCL1 (I2C). I2C0 is fine, but the 11dof port uses SPI1 and I2C1, both of the affected busses. This is fixable with a green wire and a cut trace. The board modification does not require a new stencil.
  6. I jumped in face first with the SDHC patch and got burned. The Logomatic code now no longer creates log files. I have seen through the serial port that the code is reading the configuration file, but cannot or will not write the log file. What I will do is back out the FAT32 part and just use the new SDHC part, to start with. Once the Logomatic with SDHC works, I will update the bootloader similarly, then actually try it with an SDHC card.
  7. I have been looking at the LPC2468 chip. It has a purpose built SD port, DMA everywhere, USB, Ethernet if I ever wanted to use that, lots of cool new features. It's even cheaper than the LPC2148. The only problem is that it is a 208 pin chip, and I don't know if I will ever be able to solder down such a chip. Also its 28x28mm, so it may not even fit in the Logomatic board footprint. DMA is cool because it is like an arbitrary-length FIFO for every device, anywhere in memory I want it.

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